/**
     * Returns the number of query words in the suggestion index.
     * @return The number of query words.
     */
    public long getQueryWordsNum() {
        return getNum(QueryBuilders.rangeQuery(FieldNames.QUERY_FREQ).gte(1));
    }

    private long getNum(final QueryBuilder queryBuilder) {
        final SearchResponse searchResponse = client.prepareSearch()
                .setIndices(getSearchAlias(index))